He made a surprising return for his senior season, instantly becoming a Heisman Trophy front-runner.

Like USC’s national-title chances, his shot at the Heisman appears to be gone.

Barkley has had some big games this season, but also some so-so ones, held to under 200 yards passing three times.

He opened Saturday’s game by airmailing a pass well over Lee’s head and had two interceptions in the first half.

Barkley also missed a chance to extend USC’s lead in the third quarter, overthrowing Robert Woods on what would have been an 87-yard touchdown after the defensive back trying to cover him fell.

“I’ll be thinking about that play all night,” Barkley after completing 31 of 49 passes. “I got a little too excited seeing how wide open he was and just didn’t put enough air under the ball.”

It wasn’t just Barkley.

Running backs Silas Redd and D.J. Morgan both lost fumbles, and safety Jawanza Starling gave the ball right back after an interception, fumbling it away on the return.

USC’s defense allowed Arizona to pile up 588 yards and chew up precious time on its final drive, giving up a pair of first downs even though they knew the Wildcats would be running.

USC got the ball a final time with 55 seconds left, but two passes over the middle kept the clock running, leaving no option but to heave the ball into the end zone from Arizona’s 48-yard line. Barkley’s pass sailed into a crowd of players, but fell harmlessly to the turf, sending the Wildcats jubilantly running across the field and tears streaming down Lee’s face.

“We didn’t win and that’s why I was upset,” Lee said.

The loss knocked USC (6-2, 4-2) out of the national-title picture and eight spots in the AP Top 25 to No. 18.

The Trojans still lead the Pac-12 South after Arizona State’s loss UCLA at home, but lost a chance to get some separation.

The Arizona loss also knocked some of the luster off of next week’s game against No. 2 Oregon at the Coliseum.

Instead of a showdown with potential national-title implications, the Trojans will be in the spoiler role for the Ducks’ BCS chances while trying keep their Pac-12 title-game hopes alive.

In a season that started with much higher expectations, this isn’t what they had in mind.